JPS61501654A - Pressure compensated differential pressure sensor and method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Pressure compensated differential pressure sensor and method Background of the invention 1. Field of invention The invention relates to a differential pressure sensor that is compensated by a combiator for the influence of reference pressure. do.

2. Conventional technology Measuring pressure differences in aerospace engineering requires high accuracy. In order to meet the high precision pressure difference measurement applied in science, two absolute pressure sensors are used. two absolute pressures had to be measured and then the pressure difference calculated.

This type of measurement is digitally corrected for pressure nonlinearity and temperature stability errors. Even if the required pressure is The measured difference reached about 1%. This means that the pressure difference is compared to the absolute pressure being measured. This is due to its small size.

Nonlinearity of pressure difference and temperature g! The inherent error is corrected by analog circuitry, and Differential pressure sensors whose reference pressure signal characteristics are mechanically corrected also It was not possible to meet the accuracy required for measurement. In addition, incompatibility difference using a reference pressure signal that was already available for correction by an analog circuit. Dynamic pressure sensors also failed to meet this standard◎ Summary of the invention The invention provides a correction process that represents a pressure difference between a first (reference) pressure and a second pressure. The system consists of an improved device for providing a controlled signal. This device is a pressure differential A pressure difference sensing means is provided for providing a difference sensor signal representative of the pressure difference. change The reference pressure to be measured is determined by a mechanical change (Var @Such changes can cause pressure difference detection This results in an unfavorable reference pressure influence on the means, which is reflected in the pressure difference signal. Ma Additionally, the reference pressure is determined by a reference pressure detection means that provides a reference signal representative of the reference pressure. Detected.

The reference signal may not change linearly in response to a certain reference pressure. standard The signal and the difference sensor signal are sent to a correction means, where the reference signal is 1, e.g. some non-linear Based on a reference pressure such as sexual response (corrected for changes), the difference sensor signal is It may not change linearly in response to a given pressure difference.

This difference sensor signal is an improved signal that more accurately represents the pressure difference than the difference sensor signal. To provide an output signal, there is a non-linear response such as a pressure difference, and an inverse reference pressure. A correction process is performed by the correction means for the change caused by the influence of.

In a preferred embodiment of the present invention, a temperature detection means is provided, and a pressure difference detection means is provided. detecting a temperature representative of the temperature of the means and the reference pressure sensing means and providing a temperature signal to the correcting means; provide The temperature signal may not change the detected temperature linearly. , due to the thermal expansion characteristics of the reference pressure detection means and pressure difference detection means, their accuracy may be adversely affected. It may affect. The modification means provide an improved output signal Signal for nonlinearity and reference signal for nonlinearity and temperature dependence. Furthermore, the differential sensor signal is evaluated for nonlinearity, temperature dependence, and reference pressure dependence. Correct each. There is also a fix.

To reduce the impact of other foreseeable undesirable events, such as water pressure surges , and other modifiable variables when processing the signal. In other preferred embodiments, the modification means may also be useful for modifying the signal. It is composed of a digital combiator that has the following functions. like this Functions require modification data such as large numbers of coefficients and constants. memory hands The stage is based on the characteristics of the temperature detection means, % reference pressure detection means, and pressure difference detection means. Provide coefficients and constants. Individual detection means are non-linear.

temperature dependence, and may not be uniformly affected by reference pressure; The memory means are corrected in their respective characteristics to obtain even higher accuracy. , the advantage of this invention is that it has correction data that specifically targets the individual detection means. Only one high precision differential pressure sensor is required. Reference pressure detection means Since the reference signal is corrected by the correction means, the reference signal is corrected by the correction means. This allows the use of a cheap, lightweight, shed reference pressure sensing means. .

Brief description of the drawing FIG. 1 is a block diagram showing a preferred embodiment of a corrected differential pressure sensor according to the present invention. It is a diagram.

FIG. 2 shows another preferred embodiment of the corrected differential pressure sensor shown in FIG. FIG.

FIG. 3 shows another preferred embodiment of the modified O-sensor shown in FIG. 1. FIG.

Figure 4 shows the vibration beam type difference sensor used in this invention with symbols. It is a diagram.

Figure 5 is a diagram showing symbols of the capacitive differential pressure sensor used in this invention. Ru.

FIG. 6 shows a preferred two-wire implementation of a differential pressure sensor with modifications made in accordance with the present invention. FIG. 2 is a block diagram illustrating an example.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 shows a preferred embodiment of the present invention such as a vibrating beam type pressure sensor. It is constituted by a pressure difference detection means 10. The pressure difference detection means 10 is denoted by reference numeral 12. a pressure difference between a first pressure or reference pressure shown at 14 and a second pressure shown at 14; Detect. Such a pressure difference means that the reference pressure corresponds to the local static pressure and that the For aerospace applications where the pressure of 2 corresponds to the local pitot tube pressure. This is useful in determining air data characteristics such as airspeed and angle of attack.

The pressure difference detection means 10 is connected via a conductor 18 to a difference sensor such as an oscillating voltage signal. provide a signal. The frequency of the oscillating voltage signal represents the pressure difference. This difference The signal may be other electrical or pneumatic (gas), or infrared or visible light. is defined as including electromagnetic radiation in the ultraviolet and ultraviolet portions of the spectrum. It may also be a light-acting device, or even another type of signal that creates a pressure difference. It is possible. The conductive wire 18 can be adapted to the differential sensor signal, for example a conductive wire. It can be any type of conductor. This conductor means 18 transfers the unmodified signal to a first buffer. Means, coupled to 20.

The first buffer means 20 is sold by, for example, Nashinaru Semiconductor Company. Comparator circuit composed of LM193 comparator and Fairchild Differential line driver consisting of 54IS40 driver sold by It is preferable to use a previously published conditioning circuit having the following. The first batch above The filter means 20 conditions the differential sensor signal, The difference sensor is connected by conducting means 22 such that the modifying means 24 is coupled to the difference sensor signal. It is for guiding the signal to the correction means 24.

The correcting means 24 are preferably digital combinators, with counters 25, 27 and an analog-to-digital converter 29. . The converter 29 converts the differential sensor signal or other signal into a digital signal compatible with the correction means 24. It is suitable for converting to a file format.

The first pressure indicated by reference numeral 12 is also detected by reference pressure detection means 26. Ru. The reference pressure detection means 26 is a batch-produced silicon piezoresistive pressure detection sensor. An inexpensive unmodified dust absolute pressure sensor, such as a sensor or solid state pressure sensor.

The reference pressure detection means 26 detects the reference pressure and detects the analog voltage or its frequency. An oscillating voltage representative of the reference pressure or other voltage transmitted by conductor 28. Format reference signal.

A second buffer means 30 is provided. The second buffer means 30 is.

It serves to separate the reference pressure detector R26 from the correction means 24. The second buffer means 30 comprises a Fairchild ionic filter for conditioning the reference signal. A differential consisting of 541 and 40 drivers sold by Industries, Inc. L, which has a line driver and is sold by National Semiconductor Company. Preferably, it consists of a conditioning circuit such as an M193 comparator. stomach. The reference signal is then guided by the conducting means 32 to the modifying means 24 . Reference pressure When using a piezoresistive sensor having an analog output as the force detection means 26, The second buffer means 30 consists of an operational amplifier, and the converting means 25 consists of an analog amplifier. It consists of a digital converter.

The temperature detection means 34 may be, for example, manufactured by McGregor, Manchester, New Hampshire. - Story) 195,03102. AMF's electric parts division is in charge. Positive temperature It is a type 7006 with a power coefficient of 5600Ω±2%. This detection means 34 is a pressure difference detection means preferably in the same temperature state as the reference pressure sensitive means 26; In order to detect the temperature of 1o, a suitable Preferably, it is arranged in close thermal contact therewith. The temperature detection means 34 is an example. For example, the temperature of an analog voltage or other form of signal representative of the temperature of the pressure difference detection means 10. provide a signal. The temperature signal is guided to third buffer means 38 by conduction means 36. He conditions the temperature signal so that it is guided to the modification means 24 by the conduction means 4°. to kick The third buffer means 38 is available from National Seba Conductor Company. A model LM158 operational amplifier may be used.

The modification means 24 are preferably provided by software or firmware. Execute the specified routine. Such a routine compares said reference signal with a reference signal. On the other hand, the difference sensor signal is processed as a function of the reference signal and the temperature signal. appropriate lookup techniques for corrective processing as a function of the signal and difference sensor signals. It consists of a function of the form such as a table or a polynomial function, and is implemented on line 41. A qualitatively modified output is preferably provided in the form of a digital signal. The above output or digital signal representing the pressure difference for direct readout or for control purposes. It can be converted into a 20mA signal or other forms of signal. The pressure difference sensing means lO may not respond exactly linearly to a given pressure difference. Not possible. The resulting differential sensor signal from the pressure differential sensing means 10 has a certain non-linear Contains linearity.

The reference pressure also has an effect such that the pressure difference detection means lO are not representative of the pressure difference. Sometimes. At various magnitudes of the reference pressure, the EE force difference detection means 10 detects a difference sensor. Based on the reference pressure dependence of sensor signals, even if they respond to the same pressure difference, there will be a somewhat specific difference. Generates a sensor signal.

The pressure difference detection means 10 are also influenced by temperature.

This is based on the temperature dependence of the difference sensor signal and is a response that is not representative of the pressure difference. This is due to changes in the coefficient of thermal expansion that cause the At least a pressure difference detection means As long as the above-mentioned nonlinearity, reference pressure dependence, and temperature dependence of 10 are repeated, Therein, the differential sensor signal is adjusted and substantially modified by the modification means 24. other The foreseeable dependencies can likewise be substantially modified by the modifying means 24. can. Other repeated non-directions of the reference pressure sensing means 26 reflected in the reference signal Linearity and temperature dependence also correct the temperature signal for a more accurate correction process of the difference sensor signal straightened by means.

The first function performed by the modification means 24 for the modification processing of the signal is linear. It consists of a series of polynomials.

Qma + bx + ax +-・-・Here, Q- output signal Xtomi2O-2 zo constant number 2-Differential sensor signal Also, a m a(, + a, Y + a, Y" + -...b" b, +1),! + b, Y”+・・・・−・Here “f” MRo-R R0 = constant R-Reference signal Also, a6=a(16+a01T+a62T+・-・-a, wa, 0+ a ,,T+ a, 2T + -・-Also, bo-t+0゜+11,1T + b otT”+ −−−−−−−Here, T−temperature signal '00 e '01 m "02 m"°, boo, bO,, -.

000 * cO,, ++ I ate l att e”’ Constant number first box The order of numbers is Z, R with respect to the detected pressure difference.

is large enough to reflect a significant correlation of T).

The first function can be simplified to satisfy the following preferred second function 0 Q = (Z + ao + alR + a, R') (1 + C, + c, R+ c, R” + c, R”) −+40 where %aOIaI+ a2+ C11I CIlc,, cstao corresponds to the first function, but this has a constant different from that of . Polynomial function of temperature signal of third or lower order It is◎ Correct differential sensor signals for nonlinearity, reference pressure dependence, and temperature dependence Other functions or means are within the scope of this invention. For example, the differential sensor signal and the base The quasi-signal and the temperature signal are combined in order to satisfy one or more of the above functions. Motorola 68 based on airborne data combiator or airborne atmospheric data combiator A correction means 24 comprising a 00 series microprocessor performs correction processing. It becomes possible to be understood.

For a given pressure difference, the difference sensor signal changes linearly. 1st and 2nd box The number of @reference signal and temperature signal that satisfies such linearity by appropriate selection of constants A constant linear response of is also satisfied in the same way.

The first and second functions require a number of constants consisting of modified values or data. Repair The positive data is appropriately selected to represent the characteristics of the pressure difference detection means 10, and the result is As a result, certain non-linearity and temperature g! existence and reference pressure dependence. Correctly corrected by the correcting means 24. Pressure difference detection means 10° Reference pressure detection means 26 and the temperature detection means 34, different known reference pressures, temperatures, and pressure differences are applied. available. The difference sensor signal, reference signal, 'J6 and temperature signal are then are recorded against reference pressures, temperatures, and pressure differences.

Such a recorded signal is then subjected to a method such as a least squares fitting method (18 Adapt to the second function using a8t 5quares fit m5thod) as a result, the reference signal, temperature signal, and difference sensor signal have improved output signals. amended to provide the issue. The modified values are then stored in memory means 42. child Values such as can be determined theoretically from known design characteristics and can also be The constituent materials (elements) of the means 10 or the average of the data are applicable to any pressure difference detection means lO. It can be applied to

The memory means 42 is 1, for example, 5484 sold by National Semiconductor Company. 72 Programmable Read Only Memory (FROM’)-like read ・Only memory elements are preferable ・This read-only memory has non-linearity, Specific characteristics of pressure difference detection means 1° regarding reference pressure dependence and temperature dependence It is established from modified data such as coefficient rings and constants representing . Memory means 42 Also includes core memory, such as disk, tape, or other similar memory devices. It can also be integrated into the correction means 24. Corrected data is preferred The non-linearity and temperature dependence of the reference pressure detection means 26 and the temperature detection means 3 It also represents some nonlinearity of 4. The memory means 42 stores information from the modifying means 24. When addressed through address line 44, memory means 42 is enabled. An enable signal (enable signal) is transmitted through the bull line 48 and a data line Known duta through 46.

Each is provided to the correction means 24.

The first and second functions simultaneously modify the temperature signal, the reference signal, and the difference sensor signal and output Generates a force signal. However, it is not necessary that the modifications be made simultaneously.

For example, in a preferred embodiment, the correction means 24 corrects the temperature signal for non-linearity. The reference signal is then corrected for nonlinearity and temperature dependence. ultimately the difference The sensor signal is corrected for nonlinearity, temperature dependence, and reference pressure dependence. , provides an output signal. Each correction is the same as the previously corrected signal and the temperature signal is corrected. It is a function of the later revised value. Other correction routines are within the scope of this invention. Ru.

In another preferred embodiment, shown in FIG. 2, each component is the same as in FIG. 1, and the reference pressure detection means 26 is attached to the housing of the pressure difference detection means 10. physically coupled to. The common retrace line also includes O memory means 42, indicated at 50. Further, the O temperature detection means 34 which is physically coupled to the housing of the pressure difference detection means 1O is , the detected temperature represents the temperature of the pressure difference detection means 10 and the reference pressure detection means 26. As shown, the pressure difference detection means 10 and the reference pressure detection means 26 are physically ◎ Pressure difference detection means 10, reference pressure detection means 26, temperature detection means 34, and memory Means 42, when physically coupled together, constitute a sensor module 60. . Revised data is culminated from testing or completed theoretical analysis. Nonlinearity, temperature The characteristics of each sensor module 60 are determined by the temperature dependence and the reference pressure dependence. Modified data representing and other modifiable variables are stored in the memory means "2". It will be done. The sensor module 60 then performs the routine performed by the modifying means 24. is interconnectably coupled with the modification means 24 without changing. Also, the correction method Stage 24 includes a temperature signal, a reference signal and a difference sensor to provide an improved output signal. Modify the signal as a function of the difference sensor signal, the reference signal, the temperature signal, and the modified data. Process.

This invention provides only one expensive sensor with approximately the same cost as one accurate absolute pressure sensor. Since only an accurate pressure difference detection means 10 is required, two absolute pressure sensors are used. It will be cheaper than when Memory hand by actual test of Sensor Mosier 60 By determining the data for sensor module 60 stored in stage 42 , nonlinearity, reference pressure dependence, temperature dependence, and reference pressure of the pressure difference detection means lO The nonlinearity and temperature dependence of the force detection means 26 and the nonlinearity of the temperature detection means 34 are , included in the data.

Thus, for example silicon piezoresistive sensors or solid state pressure sensors in batch production. An inexpensive pressure sensor such as can be used as the reference pressure sensor 26.

Such sensors have high temperature and other dependencies of the order of 10 to 20%. However, this error can be reduced to less than 2% of full scale by the corrector R24. amended within or below. The inherent small size of such sensors It is heavier and requires more space than the Nsa Mojini J 60. 2 Aerospace cargo (packag. ◎This advantage in terms of cargo is This is even better shown in Figure 3. In Figure 3, the components are They are numbered the same as those in Figure 2, but with an “A” added next to each number. ing. In the same figure, the housing of the pressure difference detection means 10A includes a reference pressure detection means 26M. Built-in. The above-mentioned cargo advantage is that the pressure difference detection means has a memory means in the casing of 10 mm. By incorporating 42A and temperature detection means 34, the improvement can be further improved.

As mentioned above, the pressure difference detection means in FIG. The vibrating beam type pressure sensor which is the subject of the specification of No. 053 is preferred. The license is assigned in the same assignment format as this application and is cited herein by reference. It is something that In FIG. 4, as shown in US Pat. No. 4,311,055, A portion of the vibrating beam 427 such as O isolator portions 437 and 44V located between V and 44V are Tension that represents.

Supports vibrating beam section 427 under compressive stress or load. Capacitive electrode 6 1V forms a capacitance with the beam section 42V and represents the pressure difference between the beam sections 42V and 42V. Extract the vibration frequency of. Vibrating beam pressure sensors are useful in aerospace applications. @The linearity, temperature, and reference pressure correction processes described above are based on a certain reference pressure. This greatly improves performance.

In another preferred embodiment, the pressure difference detection means 10 of FIG. No. 3,646, assigned in Assignment Ceremony and herein incorporated by reference. , 538, or the sensor disclosed in this application. July 27, 1981, transferred in the same transfer ceremony and cited herein by reference. Capacitive sensor disclosed in U.S. Patent Application No. 287,307 filed on , in which known circuits are combined, or assigned in the same assignment form as this application. , U.S. Pat. No. 4,370,890, herein incorporated by reference. It consists of a known circuit coupled to a transducer.

Detected by the capacitive sensor disclosed in U.S. Pat. No. 3,646,538, cited above. The pressure difference produced is the reference pressure and a second pressure corresponding to the fluid pressure in the pipe. of a fluid passing through an orifice in a conduit such that Useful when determining speed. A capacitive sensor is shown in Figure 5 and is It includes a detection diaphragm 21 as disclosed in Patent No. 3,646,538. It is equipped. The position of the diaphragm 21 depends on the pressure difference applied thereto. Change.

There are capacitor electrodes 390 and 400 on both sides of the detection diaphragm 21. Detection da The change in capacitance between the diaphragm 21 and the diaphragm (pole) plate 390.40 (!) is It represents the pressure difference.

The performance (pθrformance) of the capacitive sensor is determined by the linearity and temperature of this invention. and is greatly enhanced by the reference pressure adjustment function. Applied to many fluids When the velocity is multiplied, the reference pressure is the magnitude of a higher order than the pressure difference you want to detect. It can be done. Attempting to use two absolute pressure sensors will fail. Ru. This is because the full-scale error is large compared to the pressure difference. It is. The reference pressure error of prior art differential pressure sensors is also This is large compared to the power difference. This invention corrects the reference pressure and thereby 〇 This invention also meets the criteria to be evaluated. Design considerations other than pressure constancy, nonlinearity, and temperature constancy (dθ8ign eon81-a@ration). Repeatability of performance is of primary importance. The key point. Materials and circuit design may vary depending on time, temperature, pressure, and and the repeatability of linearity performance (performance θ). be done. Once repeatability errors are corrected by this invention, proper material and mechanical By making appropriate design choices, long-term performance can be improved. Ru.

As explained above and as explained below, the present invention provides a power supply in a conventional manner. Prepare 0 FIG. 6 shows a supplementary JIEj type differential pressure sensor 100 according to the present invention in a two-wire process. A typical arrangement for use in conjunction with a control device is shown in a block diagram. . In this case, the corrected sensor (hereinafter referred to as correction sensor) 100 is a current control device. A stage 102 is provided. The correction sensor 100 is designed to prevent pressure differences caused by DC electrical equipment. To control signals like sea urchin, eng, etc.

A control signal is provided to the current control means 102. Electrician, Hamata.

Supplying power to the correction sensor 100 as in the normal two-wire system. The two-wire device of the present invention includes a DC power source 110, which includes: First terminal 112% conductive @ll connected in series 3. Via the second input terminal 116 A line ( conductor). Next, the electrician connects the conductor leading to the second input terminal 116 and It is supplied to a second terminal 118 via a conductive wire 117. The load means 120 is connected to the second terminal 1 18 and further connected in series to the power supply 110, thus providing a two-wire power supply. The flow circuit is completed.

The load means 120 may be an actuator, a controller, a recorder, or just a first-stream instruction. It may consist of a device. The connection between the power supply 110 and the correction sensor 100 is a DC- As disclosed in U.S. Pat. No. 3,764,880 showing a DC converter. A similar configuration is also possible.

The current control means 102 controls all DC current equipment. The DC current equipment is preferably This is an industrial standard, and either a certain 420mA signal or Other forms of signals representative of the force difference and powering the correction sensor 100 It is. When the signal is 4 to 20 mA, the components of the correction sensor 10G The device operates with only 4 mA or less current when the current is 4 mA. must be selected to create.

As mentioned above, this invention can be used in determining the airspeed of an aircraft. Wear. Maryland 21401. Located at 2551 River Road, Annapolis. Aeronautical Radio Co., Ltd. (AR Kono Co., Ltd.), located in This is a company that creates standards for equipment and equipment (systems). This standard is based on companies, other aircraft operators, military authorities with similar requirements, and equipment manufacturers. A final decision will be made after investigation, coordination, and reaching a general consensus.

To determine the indicated airspeed, the air speed to be measured by this invention is The maximum pressure difference for a sonic aircraft is approximately 5.4 ps (bond/square inch) (3 7.2 kPa (kilopascal)]. The standard pressure is approximately 500 m below the water level. It is a high value of approximately 15.6 PS (107.7 kPa) under while the second pressure is at speeds approaching the speed of sound and at low altitudes about It is possible to achieve a high value of 219B (144,91CPIL). 2 pieces ARIN for commanded airspeed determination using a separate absolute pressure sensor of In order to meet the 1978 standards established by Company C, each implied section shall be The accuracy of the sensor is 0.013% full scale and 0.014% full scale, respectively. Ru. Accuracy is approximately 0.005 PS engineering (0,0341 cPa) maximum error for pressure difference. It is based on the difference.

Currently available absolute pressure sensors have an accuracy of approximately 0.02% full scale; When only one of the absolute pressure sensors is considered, the possible error is 0,0002 21 = 0.0042PS engineering (0,0002X 144.9-0.0290k Pa　). When the error of the second absolute pressure sensor is added, - i.e. the error of one absolute pressure sensor is the maximum allowable difference error. Since it is almost the same as a certain o-oosps engineering (o, oa4kpa), AR engineering NC Company i's criteria are satisfied by attempting to use two absolute pressure sensors. That's impossible.

However, this invention meets ARINC's standards. In Figure 1, the pressure differential The pressure output means 10 is used in conjunction with the reference pressure sensing means 26 to determine airspeed. The difference detection means 10 is.

At least 5.4PB (37.2kPa) corresponding to the maximum pressure difference to be measured. ) to ops engineering, and standard pressure The detection means 26 has a range of 0 to 15.6 PS (xo7.7 kpa). Next, the criterion is the worst case based on the indicated airspeed. Due to the error, the overall accuracy of the pressure difference detection means 10 is limited to a pressure difference of 0,005 PS ( In order to keep it within the range of Q, Q34kPa), the It implies that it must be. Difference caused by reference pressure dependence The sensor signal variation is 0.25% relative to a reference pressure equal to the full-scale differential pressure. full scale, which is required to meet ARINC standards. This sufficiently exceeds the required overall accuracy of 0.09% full scale.

When the overall accuracy of the reference pressure detection means 26 is 2%, the reference pressure dependence is 50=1. correction can be achieved. The reference pressure for subsonic aircraft is at an altitude of approximately 12,600 m. Soo from the water level of 2.56PS (i7.6kPa) at , 15.6 Pa (107,6 kPa) below, the overall 3PS engineering (90kPa) changes. This change is caused by the full scale of the pressure difference detection means 1o. This doubles the overall reference pressure dependence and increases the full-scale 0. Make it 5%.

Therefore, the correction of 50:l reduces the dependence of the pressure difference detection means 10 on the reference pressure, and this The accuracy with respect to the reference pressure dependence is 0.01% full scale or 0.000 As a result, this Embodiments of the invention perform better than ARINC standards. Therefore, this invention Even higher performance standards than currently required are met.

The sensor device assembled according to this invention has the advantage of improving the accuracy of pressure difference measurements. , was tested to determine the utility of this invention. The sensor device takes into account the correction When introduced, it easily exceeded ARINC's standards. The sensor device uses the second function used. Such a sensor device has a pressure of 0 to 16P13 (110kPa). It consisted of a vibrating beam type pressure difference detection means and an IQ button on the range. Such sensor device Now, let's take a look at more than what you would expect to encounter in subsonic aerospace applications. Actual pressure difference during exposure to a wide range of temperatures, reference pressures, and pressures of 2iK The worst overall fluctuation from 0.0021 Pa (0,015 kPa) to 0 ．． It changed to 0039 Ps engineering (0,027 kPa).

FIG.1

Claims (33)

[Claims] 1. detecting a pressure difference between the first pressure and the second pressure; an output signal representative of the pressure difference; An apparatus for providing, the apparatus comprising: pressure difference sensing means for providing a difference sensor signal representative of said pressure difference; reference pressure sensing means for providing a reference sensor signal representative of the first pressure; memory means for providing correction data and said reference sensor signal and said correction; correcting the reference sensor signal as a function of data; providing an output signal as a function of the sensor signal, the difference sensor signal and the modified data; and correction means for making the output signal more representative of the pressure difference. Pressure difference detection device. 2. The differential sensor signal does not vary linearly in response to a pressure difference, and The positive data is based on the data representing the non-linearity of the difference sensor signal. A device according to scope 1. 3. The reference sensor signal does not change linearly in response to a certain first pressure, and The correction data is formed from data representing nonlinearity of the reference sensor signal. A device according to claim 1. 4. The differential sensor signal does not change linearly in response to a certain pressure difference, and The positive data is further established from the data representing the nonlinearity of the difference sensor signal. The device according to claim 3. 5. the differential sensor signal is influenced by the first pressure and the modified data is established from data representing the influence of the first pressure on the differential sensor signal. A device according to claim 1. 6. The difference sensor signal does not change linearly in response to a certain pressure difference, and the correction The data further comprises data representative of the non-linearity of the differential sensor signal, and Furthermore, the reference sensor signal does not vary linearly in response to a certain first pressure; The corrected data is further established from data representing non-linearity of the reference sensor signal. 6. The apparatus according to claim 5. 7. further comprising temperature sensing means for providing a temperature signal representative of the temperature of said device; 7. An apparatus as claimed in claim 6 comprising: 8. The reference sensor signal is influenced by the temperature of the device and is also influenced by the correction data. data representing the influence of the temperature on the reference sensor signal. 8. The device according to claim 7. 9. The differential sensor signal is influenced by the temperature of the device and is also influenced by the modified data. is established from data representing the influence of the temperature on the differential sensor signal. The device according to item 8 of the scope of demand. 10. The temperature signal does not vary linearly with a certain temperature of the device and The corrected data is based on data representing non-linearity of the temperature signal. A device according to scope 9. 11. Further, temperature sensing means for providing a temperature signal representative of the temperature of said device. An apparatus according to claim 1, comprising: 12. The correction means is based on the following formula: a+bx+cx2+... Here, x=Z0-Z Z = difference sensor signal Z0=corrected data Also, a=a0+a1Y+a2Y2+...b=b0+b1Y+b2Y2+... c=c0+c1Y+c2Y2+... Here, Y=R0-R R = reference sensor signal R0=corrected data Also, a0=a00+a01T+a02T2+...a1=a10+a11T+a 12T2+...a2=a20+a21T+a22T2+...Also, b0=b00 +b01T+b02T2+...b1=b10+b11T+b12T2+...again , c0=c00+c01T... Here, T=temperature signal a00, a01..., b00, b01,..., c00, c01,..., a10, a1 1,... = a digital computer that provides said output signal according to the modified data; 12. The apparatus of claim 11 comprising: 13. Some correction data is selected to have a value of zero, and the above formula a+bx+cx2+... is the formula (Z+a0+a1R+a2R2)(1+c0+clR+c2R2+c3R3 )+d0, where a0, a1, a2, c0, c1, c2, c3, do is the third or lower order temperature signal having mutually different correction values; 13. The device of claim 12, wherein the device is a function of . 14. The reference pressure sensing means is physically coupled to the pressure difference sensing means and The modification means is configured to modify the reference sensor signal at the same time as modifying the difference sensor signal. The device according to item 11. 15. The temperature detection means is physically coupled to the pressure difference detection means in a thermally intimate state. and the correction means adjusts the reference sensor signal and the difference sensor signal. 15. The apparatus of claim 14, wherein the temperature signal is also modified at the same time as the modification. 16. The pressure difference detection means, reference pressure detection means, temperature detection means, and memory hand such that the stage is constituted by a sensor module exchangeably connected to said modifying means; Claim 1, wherein said memory means is physically coupled to said pressure difference detection means. The device according to item 15. 17. Claim 1 wherein said memory means comprises a read-only memory. The device according to item 6. 18. Connected to two wires from the DC power source and the load connected in series, and The device according to claim 1, having two terminals through which a direct current signal flows. The device is further characterized in that the direct current signal is representative of a pressure difference and that the device is controlling said DC current signal as a function of said output signal so as to provide one energization; Claim 1 further comprising current control means coupled to said two terminals for The device described. 19. Further, temperature sensing means for providing a temperature signal representative of the temperature of said device. 19. The apparatus of claim 18, comprising: 20. The DC current signal comprises a signal varying between 4 mA and 20 mA. Apparatus according to scope 18. 21. The differential sensor signal transmitted by the differential pressure sensor and the reference pressure sensor used by the correction device to automatically correct the reference sensor signal transmitted by the 1. A method for determining a number of correction values for determining the differential pressure, the method comprising: exposing the sensor and said reference pressure sensor to a number of known reference pressures and pressure differences; and, Recording the differential sensor signals at different known reference pressures and pressure differences. The process of recording the reference sensor signal at a known reference pressure and pressure difference; determining the correction value based on the recorded difference sensor signal and the reference sensor signal; The process of storing said modified values in a memory device. 22. determining a pressure difference between a first pressure and a second pressure; and an output representative of the pressure difference. A method of providing a force signal, the method comprising: detecting the pressure difference; providing a difference signal representative of the detected pressure difference; and detecting the first pressure. The process of providing a reference signal representative of the detected first pressure; a process of accumulating correction values; modifying the reference signal as a function of the reference signal and the accumulated modification value; The process of a function of the modified reference signal, the difference signal, and the accumulated modification value; and providing the output signal as described above. 23. The pressure difference is detected by a differential pressure sensor, and the first pressure is a reference pressure set. the corrected value is stored in a memory device and also in a digital computer. claim 1, wherein the computer processes the reference signal and provides the output signal. The method according to paragraph 22. 24. The differential pressure sensor is a capacitive differential pressure sensor. The method described in Section 23. 25. The differential pressure sensor may be a vibrating beam type differential pressure sensor. The method according to paragraph 23. 26. The reference pressure sensor is an absolute pressure sensor that can be corrected to an accuracy of 2% or less. 24. The method according to claim 23, wherein the method comprises: 27. The memory device is comprised of a read-only memory. The method described in Section 23. 28. The reference signal exhibits some nonlinearity, and the difference signal exhibits some nonlinearity and 24. A method according to claim 23, showing the influence of pressure of 1. 29. The correction value is determined by the digital computer to make the reference signal non-linear. and correcting the difference signal for nonlinearity and the effects of a first pressure. , the nonlinearity of the reference signal, the nonlinearity of the difference signal, and the influence of the first pressure. 29. The method according to claim 28, wherein the method is based on data representing a sound. 30. determining a pressure difference at a variable temperature between a first pressure and a second pressure; A method of providing an output signal representative of a pressure difference, the method comprising: a step of detecting the pressure difference; providing a difference signal representative of the detected pressure difference; and detecting the first pressure. The process of providing a reference signal representative of the detected first pressure; a process of detecting temperature; providing a temperature signal representative of the detected temperature; and storing a correction value. and, modifying the temperature signal as a function of the temperature signal and the accumulated modification value; the process of managing a box of the corrected temperature signal, the reference signal, and the accumulated correction values; as a number, modifying the reference signal; the modified temperature signal, the modified reference signal, the difference signal, and , providing the output signal as a function of the accumulated correction value. The way it is. 31. The pressure difference is detected by a differential pressure sensor, and the first pressure is a reference pressure. the temperature is detected by a temperature sensor and the corrected value is detected by a temperature sensor; is stored in a memory device, and a digital computer combines said temperature signal and said basis. 31. The method according to claim 30, wherein the method modifies the quasi-signal and provides the output signal. Law. 32. The digital computer has the following formula: a+bx+cx2 Here, x=Z0-Z Z=the difference signal Z0=correction value Also, a=a0+a1Y+a2Y2+...b=b0+b1Y+b2Y2+... c=c0+c1Y+c2Y2+... Here, Y=R0-R R=the reference signal R0=correction value Also, a0=a00+a01T+a02T2+...a1=a10+a11T+a 12T2+...a2=a20+a21T+... Also, b0=b00+b01T+b02T2+...b1=b10+b11T+... … Also, c0=c00+c01T+... Here, T=the temperature signal a00, a01,..., b00, b01,..., c00, c01,..., a10, a1 32. The method according to claim 31, wherein the output signal is provided according to 1,... = modified value. Law. 33. A certain correction value is chosen to have a zero value, and the above formula 2 a+bx+cx2+... is the expression (Z+a0+a1R+a2R2) (1+c0+clR+c2R2+c3R3)+ d0, where a0, a1, a2, c0, c1, c2, c3, d0 is a function of the temperature signal of order less than or equal to 3 with mutually different corresponding correction values. 33. The method of claim 32.